Use unknown for queries failed to classify their DB roles

Issue https://gitlab.com/gitlab-com/gl-infra/scalability/-/issues/965

ee/lib/ee/peek/views/active_record.rb

@@ -11,7 +11,8 @@ def generate_detail(start, finish, data)
           detail = super
 
           if ::Gitlab::Database::LoadBalancing.enable?
-            detail[:db_role] = ::Gitlab::Database::LoadBalancing.db_role_for_connection(data[:connection]).to_s.capitalize
+            role = ::Gitlab::Database::LoadBalancing.db_role_for_connection(data[:connection]) || :unknown
+            detail[:db_role] = role.to_s.capitalize
           end
 
           detail

ee/spec/lib/peek/views/active_record_spec.rb

@@ -8,6 +8,7 @@
   let(:connection_replica) { double(:connection_replica) }
   let(:connection_primary_1) { double(:connection_primary) }
   let(:connection_primary_2) { double(:connection_primary) }
+  let(:connection_unknown) { double(:connection_unknown) }
 
   let(:event_1) do
     {
@@ -36,11 +37,21 @@
     }
   end
 
+  let(:event_4) do
+    {
+      name: 'SCHEMA',
+      sql: 'SELECT VERSION()',
+      cached: false,
+      connection: connection_unknown
+    }
+  end
+
   before do
     allow(Gitlab::PerformanceBar).to receive(:enabled_for_request?).and_return(true)
     allow(connection_replica).to receive(:transaction_open?).and_return(false)
     allow(connection_primary_1).to receive(:transaction_open?).and_return(false)
     allow(connection_primary_2).to receive(:transaction_open?).and_return(true)
+    allow(connection_unknown).to receive(:transaction_open?).and_return(false)
   end
 
   context 'when database load balancing is not enabled' do
@@ -49,6 +60,7 @@
         ActiveSupport::Notifications.publish('sql.active_record', Time.current, Time.current + 1.second, '1', event_1)
         ActiveSupport::Notifications.publish('sql.active_record', Time.current, Time.current + 2.seconds, '2', event_2)
         ActiveSupport::Notifications.publish('sql.active_record', Time.current, Time.current + 3.seconds, '3', event_3)
+        ActiveSupport::Notifications.publish('sql.active_record', Time.current, Time.current + 4.seconds, '4', event_4)
       end
 
       expect(subject.results).to match(
@@ -80,6 +92,13 @@
             transaction: 'In a transaction',
             duration: 3000.0,
             sql: 'UPDATE users SET admin = true WHERE id = 10'
+          ),
+          a_hash_including(
+            start: be_a(Time),
+            cached: '',
+            transaction: '',
+            duration: 4000.0,
+            sql: 'SELECT VERSION()'
           )
         )
       )
@@ -92,6 +111,7 @@
       allow(Gitlab::Database::LoadBalancing).to receive(:db_role_for_connection).with(connection_replica).and_return(:replica)
       allow(Gitlab::Database::LoadBalancing).to receive(:db_role_for_connection).with(connection_primary_1).and_return(:primary)
       allow(Gitlab::Database::LoadBalancing).to receive(:db_role_for_connection).with(connection_primary_2).and_return(:primary)
+      allow(Gitlab::Database::LoadBalancing).to receive(:db_role_for_connection).with(connection_unknown).and_return(nil)
     end
 
     it 'includes db role data' do
@@ -99,6 +119,7 @@
         ActiveSupport::Notifications.publish('sql.active_record', Time.current, Time.current + 1.second, '1', event_1)
         ActiveSupport::Notifications.publish('sql.active_record', Time.current, Time.current + 2.seconds, '2', event_2)
         ActiveSupport::Notifications.publish('sql.active_record', Time.current, Time.current + 3.seconds, '3', event_3)
+        ActiveSupport::Notifications.publish('sql.active_record', Time.current, Time.current + 4.seconds, '4', event_4)
       end
 
       expect(subject.results).to match(
@@ -135,6 +156,14 @@
             duration: 3000.0,
             sql: 'UPDATE users SET admin = true WHERE id = 10',
             db_role: 'Primary'
+          ),
+          a_hash_including(
+            start: be_a(Time),
+            cached: '',
+            transaction: '',
+            duration: 4000.0,
+            sql: 'SELECT VERSION()',
+            db_role: 'Unknown'
           )
         )
       )